Adjusting Starret depth Mics?

Hey Guys,

I just use my depth mics for a ref tool on +/-.003 spring pockets mostly and I want to make sure I'm good. Our shop uses all mits and they are used to checking them, not mine.

I use the inspectors 123 blocks to check my 1 to 3 set. I don't have a box or wrench since i bought then, in great shape, from ebay a few years ago.

I'm within .001 on all stems, but want it to be closer.

Walt

The Starrett depth mics adjust much the same as the Mitutoyo; with two nuts at the back end of the rod. You'll need to come up with a couple of adjusting wrenches (one of which could be a 4" adjustable wrench) to get yours closer. You might find something out of an ignition wrench set that fits fine.

The accuracy of 1-2-3 blocks varies. Some imports aren't that accurate. Some good old blocks may be worn or even reground. Make sure you have a good standard (which could also be gage blocks or a purpose-made mic testing fixture) before attempting adjustment.

In actual use, it's often pretty easy to fool yourself when trying to measure to a couple tenths with a depth mic. The base may not be seated, the seating area may not be flat, the rod may dig in a bit, and so on.

Thanks,

The 123 blocks I use are calibrated by a service for inspection at work so they should be ok for what is needed I think, not the shop grade I use on some setups. Lol

It seamed they were just axial split nuts on my set. How to hold the stem?

Not sure, an I missing something?

Sorry, 'around' zero on depth mics is way ok! I try to hold tight and steady, not look but feel, and hold the barrel as I look. Usualy twice.

walt

ScrapWood said:

It seamed they were just axial split nuts on my set. How to hold the stem?

Click to expand...

I use a 5C collet and a collet block. Maybe not the quickest way to do it but it works quite well for me.

Adjusting a Starrett depth rod

The collet idea is a great one and was used in labs where I once worked in the1980s. Soft-jaws for a bench vise will work almost as well.

Your two main concerns [accuracy aside] are; don't score the rod- and; don't spring the rod. One pro-active step that should be taken is to expose no more than 20-25 % of the rod length above the top of the holding point when positioning the rod for adjustment. This stiffens the rod/ reduces flex.

See my attached pic.

Ed Hopson

Ed - The old saying about "a picture is worth a thousand words" is certainly true here. Yours is an excellent example of the PROPER way to adjust the individual rods. Thanks!

Thanks Top & Ed,

I'm still working on my box but I always buy good quality when it matters. I try to take care of things best I can, and this helps.

Great pic.

Did it in the small colchester with a collet closer at work, but may round up a bit of thick rubber sheet and use a kurt with the stem sideways next time.

Walt